ardupilot/libraries/AP_Proximity/AP_Proximity_Boundary_3D.h

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/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "AP_Proximity.h"
#if HAL_PROXIMITY_ENABLED
#include <Filter/LowPassFilter.h>
#define PROXIMITY_NUM_SECTORS 8 // number of sectors
#define PROXIMITY_NUM_LAYERS 5 // num of layers in a sector
#define PROXIMITY_MIDDLE_LAYER 2 // middle layer
#define PROXIMITY_PITCH_WIDTH_DEG 30 // width between each layer in degrees
#define PROXIMITY_SECTOR_WIDTH_DEG (360.0f/PROXIMITY_NUM_SECTORS) // width of sectors in degrees
#define PROXIMITY_BOUNDARY_DIST_MIN 0.6f // minimum distance for a boundary point. This ensures the object avoidance code doesn't think we are outside the boundary.
#define PROXIMITY_BOUNDARY_DIST_DEFAULT 100 // if we have no data for a sector, boundary is placed 100m out
#define PROXIMITY_FILT_RESET_TIME 1000 // reset filter if last distance was pushed more than this many ms away
#define PROXIMITY_FACE_RESET_MS 1000 // face will be reset if not updated within this many ms
class AP_Proximity_Boundary_3D
{
public:
// constructor. This incorporates initialisation as well.
AP_Proximity_Boundary_3D();
// stores the layer and sector as a single object to access and modify the 3-D boundary
// Objects of this class are used temporarily to modify the boundary, i,e they are not persistant or stored anywhere
class Face
{
public:
// constructor, invalidate id and distance
Face() { layer = sector = UINT8_MAX; }
Face(uint8_t _layer, uint8_t _sector) { layer = _layer; sector = _sector; }
// return true if face has valid layer and sector values
bool valid() const { return ((layer < PROXIMITY_NUM_LAYERS) && (sector < PROXIMITY_NUM_SECTORS)); }
// comparison operator
bool operator ==(const Face &other) const { return ((layer == other.layer) && (sector == other.sector)); }
bool operator !=(const Face &other) const { return ((layer != other.layer) || (sector != other.sector)); }
uint8_t layer; // vertical "steps" on the 3D Boundary. 0th layer is the bottom most layer, 1st layer is 30 degrees above (in body frame) and so on
uint8_t sector; // horizontal "steps" on the 3D Boundary. 0th sector is directly in front of the vehicle. Each sector is 45 degrees wide.
};
// returns face corresponding to the provided yaw and (optionally) pitch
// pitch is the vertical body-frame angle (in degrees) to the obstacle (0=directly ahead, 90 is above the vehicle?)
// yaw is the horizontal body-frame angle (in degrees) to the obstacle (0=directly ahead of the vehicle, 90 is to the right of the vehicle)
Face get_face(float pitch, float yaw) const;
Face get_face(float yaw) const { return get_face(0, yaw); }
// Set the actual body-frame angle(yaw), pitch, and distance of the detected object.
// This method will also mark the sector and layer to be "valid",
// This distance can then be used for Obstacle Avoidance
// Assume detected obstacle is horizontal (zero pitch), if no pitch is passed
void set_face_attributes(const Face &face, float pitch, float yaw, float distance);
void set_face_attributes(const Face &face, float yaw, float distance) { set_face_attributes(face, 0, yaw, distance); }
// update boundary points used for simple avoidance based on a single sector and pitch distance changing
// the boundary points lie on the line between sectors meaning two boundary points may be updated based on a single sector's distance changing
// the boundary point is set to the shortest distance found in the two adjacent sectors, this is a conservative boundary around the vehicle
void update_boundary(const Face &face);
// reset boundary. marks all distances as invalid
void reset();
// Reset this location, specified by Face object, back to default
// i.e Distance is marked as not-valid
void reset_face(const Face &face);
// check if a face has valid distance even if it was updated a long time back
void check_face_timeout();
// get distance for a face. returns true on success and fills in distance argument with distance in meters
bool get_distance(const Face &face, float &distance) const;
// Get the total number of obstacles
uint8_t get_obstacle_count() const;
// Returns a body frame vector (in cm) to an obstacle
// False is returned if the obstacle_num provided does not produce a valid obstacle
bool get_obstacle(uint8_t obstacle_num, Vector3f& vec_to_boundary) const;
// Returns a body frame vector (in cm) nearest to obstacle, in betwen seg_start and seg_end
// True is returned if the segment intersects a plane formed by considering the "closest point" as normal vector to the plane.
bool closest_point_from_segment_to_obstacle(uint8_t obstacle_num, const Vector3f& seg_start, const Vector3f& seg_end, Vector3f& closest_point) const;
// get distance and angle to closest object (used for pre-arm check)
// returns true on success, false if no valid readings
bool get_closest_object(float& angle_deg, float &distance) const;
// get number of objects, angle and distance - used for non-GPS avoidance
uint8_t get_horizontal_object_count() const;
bool get_horizontal_object_angle_and_distance(uint8_t object_number, float& angle_deg, float &distance) const;
// get number of layers
uint8_t get_num_layers() const { return PROXIMITY_NUM_LAYERS; }
// get raw and filtered distances in 8 directions per layer.
bool get_layer_distances(uint8_t layer_number, float dist_max, AP_Proximity::Proximity_Distance_Array &prx_dist_array, AP_Proximity::Proximity_Distance_Array &prx_filt_dist_array) const;
// pass down filter cut-off freq from params
void set_filter_freq(float filt_freq) { _filter_freq = filt_freq; }
// sectors
static_assert(PROXIMITY_NUM_SECTORS == 8, "PROXIMITY_NUM_SECTOR must be 8");
const uint16_t _sector_middle_deg[PROXIMITY_NUM_SECTORS] {0, 45, 90, 135, 180, 225, 270, 315}; // middle angle of each sector
// layers
static_assert(PROXIMITY_NUM_LAYERS == 5, "PROXIMITY_NUM_LAYERS must be 5");
const int16_t _pitch_middle_deg[PROXIMITY_NUM_LAYERS] {-60, -30, 0, 30, 60};
private:
// initialise the boundary and sector_edge_vector array used for object avoidance
void init();
// get the next sector which is CW to the passed sector
uint8_t get_next_sector(uint8_t sector) const {return ((sector >= PROXIMITY_NUM_SECTORS-1) ? 0 : sector+1); }
// get the prev sector which is CCW to the passed sector
uint8_t get_prev_sector(uint8_t sector) const {return ((sector <= 0) ? PROXIMITY_NUM_SECTORS-1 : sector-1); }
// Converts obstacle_num passed from avoidance library into appropriate face of the boundary
// Returns false if the face is invalid
// "update_boundary" method manipulates two sectors ccw and one sector cw from any valid face.
// Any boundary that does not fall into these manipulated faces are useless, and will be marked as false
// The resultant is packed into a Boundary Location object and returned by reference as "face"
bool convert_obstacle_num_to_face(uint8_t obstacle_num, Face& face) const WARN_IF_UNUSED;
// Apply a new cutoff_freq to low-pass filter
void apply_filter_freq(float cutoff_freq);
// Apply low pass filter on the raw distance
void set_filtered_distance(const Face &face, float distance);
// Return filtered distance for the passed in face
bool get_filtered_distance(const Face &face, float &distance) const;
Vector3f _sector_edge_vector[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS];
Vector3f _boundary_points[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS];
float _angle[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // yaw angle in degrees to closest object within each sector and layer
float _pitch[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // pitch angle in degrees to the closest object within each sector and layer
float _distance[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // distance to closest object within each sector and layer
bool _distance_valid[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // true if a valid distance received for each sector and layer
uint32_t _last_update_ms[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // time when distance was last updated
LowPassFilterFloat _filtered_distance[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // low pass filter
float _filter_freq; // cutoff freq of low pass filter
};
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// This class gives an easy way of making a temporary boundary, used for "sorting" distances.
// When unkown number of distances at various orientations are sent we store the least distance in the temporary boundary.
// After all the messages are received, we copy the contents of the temporary boundary and put it in the main 3-D boundary.
class AP_Proximity_Temp_Boundary
{
public:
// constructor. This incorporates initialisation as well.
AP_Proximity_Temp_Boundary() { reset(); }
// reset the temporary boundary. This fills in distances with FLT_MAX
void reset();
// add a distance to the temp boundary if it is shorter than any other provided distance since the last time the boundary was reset
// pitch and yaw are in degrees, distance is in meters
void add_distance(const AP_Proximity_Boundary_3D::Face &face, float pitch, float yaw, float distance);
void add_distance(const AP_Proximity_Boundary_3D::Face &face, float yaw, float distance) { add_distance(face, 0.0f, yaw, distance); }
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// fill the original 3D boundary with the contents of this temporary boundary
void update_3D_boundary(AP_Proximity_Boundary_3D &boundary);
private:
float _distances[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // distance to closest object within each sector and layer. Will start with FLT_MAX, and then be changed to a valid distance if needed
float _angle[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // yaw angle in degrees to closest object within each sector and layer
float _pitch[PROXIMITY_NUM_LAYERS][PROXIMITY_NUM_SECTORS]; // pitch angle in degrees to the closest object within each sector and layer
};
#endif // HAL_PROXIMITY_ENABLED